Why do there always have to be a rival? Jealousy should not be necessary to consolidate a relationship.
Exactly my point with every love triangle in any romance manga! It's like jeez, trust your partner more or explain to them why you are so anxious. It pisses me off when rifts appear in relationships because of lack of a communication. It's used too much.
What is so wrong about raising another's child? I am surprised that he even cut ties with his own daughter because of it.
So no faithful people in this story.